2-PARTICLE RAPIDITY CORRELATIONS FROM THE BOSE-EINSTEIN EFFECT IN CENTRAL SI-28+AU COLLISIONS AT 14.6A GEV C AND INTERMITTENCY/

In previous work, the E802 Collaboration at the BNL-AGS used negative binomial distribution (NBD) fits to charged particle multiplicity dist ributions from central collisions of O-16+Cu at 14.6A GeV/c to derive the two-particle short-range rapidity correlation length and strength. These turned out to be much shorter and weaker than the values for ha dron collisions, which led to a simple and elegant explanation of inte rmittency. In the present work, a direct measurement of the two-partic le correlation of identified pions in the E802/E859 magnetic spectrome ter is performed in the interval 1.5 less than or equal to y less than or equal to 2.0 for central Si-28+Au collisions, both in terms of Q(i nv) = root\(q) over right arrow\(2)-q(0)(2), where q = p(2)-p(1) = ((q ) over right arrow, q(0)) and also in terms of \eta(2) - eta(1)\ and \ y(2)-y(1)\, where p, eta, and y are the four-momentum, pseudorapidity, and rapidity of the pions. It is demonstrated that the two-pion corre lation in rapidity (and pseudorapidity) is entirely due to the Bose-Ei nstein interference. The directly measured correlation length in both eta and y is xi = 0.19 +/- 0.03 for two pi(-), with strength R(0,0)sim ilar to 1%, in agreement with the previous E802 indirect measurements derived from the NBD analysis of intermittency.